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Re: If a^2=b, is the value of a between 0 and 1? [#permalink]
05 Feb 2015, 01:05
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If a^2=b, is the value of a between 0 and 1? [#permalink]
03 Sep 2015, 04:49
This post received KUDOS
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and equations ensures a solution.
If a^2=b, is the value of a between 0 and 1?
(1) b is between 0 and 1 (2) a>b
There is nothing to transform in the original condition and the question. WE have 2 variable (a,b) and 1 equation (a^2=b), thus we need 1 more to match the number of variables and equations. Since there is 1 each in 1) and 2), D is likely the answer.
In case of 1), if b=0.04 then the answer is no if a=-0.2 and yes if a=0.2 Thus it is not sufficient. In case of 2), a>b=a^2, a>a^2, 0>a^2-a, 0>a(a-1), 0<a<1, therefore the answer is yes. Thus the answer is B. _________________